Energy-absorbing impact devices absorb and/or attenuate energy during an impact event for different applications, such as an errant vehicle impacting a road hazard (roadside safety), a vehicle impacting another vehicle (vehicle crashworthiness), an occupant impacting a collapsible steering column (occupant safety), and a helicopter impacting the ground at uncontrolled velocity (collapsible landing gear for occupant safety), to name a few.
A crash cushion is an energy absorbing device that is placed in front of a fixed hazard to “cushion” the hazard. Its function is to reduce the impact severity of an errant vehicle impacting the hazard by absorbing the kinetic energy of the moving vehicle in a controlled manner when impacted head-on. A crash cushion should also be able to redirect an errant vehicle impacting on the cushion's sides since it is possible for such impacts to occur.
There are several crash cushion devices available. For example, some are barrel-based crash cushion systems, such as the Reusable Energy Absorbing Crash Terminal (“REACT”) 350 or Connecticut Impact Attenuator System (“CIAS”). Both of these systems utilize the transverse collapsing of cylinders (steel or polyethylene) to dissipate energy of an impacting object. However, these designs use circular cylinders that are oriented about a vertical rather than longitudinal axis. Thus, the cylinders are loaded and collapse in a lateral rather than end-on manner. Most of the remaining crash cushion systems utilize an energy absorbing component like a polymer cartridge (QuadGuard), a metal tearing (TRACC), or a pneumatic (air chambers) crash cushion that need another component for side impact protection, which is usually steel rails or steel plates arranged in an overlapping configuration (fish-scale pattern).